Tuesday | October 17, 2017
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Lava diversion: Can it work? Should it be considered?

Editor’s note: Since the June 27 lava flow began nearing Pahoa, the Tribune-Herald has been flooded with calls and letters from readers asking a simple question: What can be done, if anything, to divert the lava? Because of our readers’ intense interest in this subject, we’ve elected to publish this editorial on A1. Readers are encouraged to provide feedback at letters@hawaiitribune-herald.com.

Pele is now sending lava flows north of Kilauea’s East Rift Zone, and is threatening property in the Pahoa area for the first time since 1840.

Because humans now have the technical capability to alter lava flow paths under certain circumstances, I feel it is time for government agencies and the lower Puna community to re-examine “lava diversion” as a means to lessen property damage from the ongoing eruption.

For such an evaluation, two principal questions must be answered: (1) Is it technically feasible, and (2) if feasible, would the artificial diversion of lava be the pono thing to do?

Economic, legal, political and cultural realities also must be evaluated, with the realization that any decision to “mess with Mother Nature” and to interfere with Pele’s activity will always be controversial. In fact, though, we humans do “mess with Mother Nature” all the time — from simple acts such as carrying umbrellas to major projects such as flood control. Channeling water into artificial diversion spillways (such as the Alenaio Stream diversion to protect Hilo from flooding) is socially acceptable — should the potential to divert lava flows be off the table?

Lava diversion is a proven technique to protect valuable property and has been successfully carried out in Italy and Iceland, but only after major, government-supported efforts.

Lava diversion is only feasible when the terrain is favorable, where there are lesser-value lands downslope toward which flows can be directed, and when sufficient time is available to carefully plan and carry out the operations. Molten lava is a fluid, albeit a very viscous one, and like water will respond to gravity and flow along the easiest terrain pathway to lower elevations.

Three methods to divert lava flows have been used successfully in the past: (1) Use of explosives to disrupt lava flow supply conduits near eruptive vents, far from flow fronts; (2) application of large volumes of water on flow fronts to thicken flows and to form barriers of frozen lava; and (3) construction of lava deflection structures at advancing flow fronts to deflect flows toward less destructive paths.

Neither of the first two options seem appropriate for the current situation; the construction of bulldozed berms to minimize losses is the best option in the Pahoa area.

Lava diversion has been attempted several times in Hawaii (bombing operations of 1935 and 1942; barrier construction in 1955 and 1960), but none of these attempts were well-planned, and all failed. A great deal is now known about the rheology (physical properties) of flowing lava and significant engineering knowledge has accumulated about the means to construct diversion structures.

Because of the legal issues involved, however, lava diversion can only be attempted by government entities operating under the umbrella of a Federal Disaster Declaration (such as now exists in Puna) when questions of liability regarding actions to protect the public good are moot. Independent efforts to protect one’s property are ill-advised, since diversion of lava onto someone else’s property by private individuals will invariably involve liability issues.

I, like most long-term Hawaii residents, have great respect for Pele, and the diverse opinions of Hawaiian people about the question of lava diversion must be seriously considered. Most Hawaiians I’ve spoken with say something like, “You can mess with Pele if you want, but she’s going to do what she wants to do in any event.” I basically agree, and would approach any lava diversion attempts not in an effort to “Stop Pele” or to confront her, but in a spirit of cooperation — using an earthen wall to politely request that she might want to follow a different path.

Any such attempts should involve Hawaiian practitioners who know best how to explain to Pele what we might like her to do. Princess Ruth set a good example in July 1881 when she spoke to Pele from the Halai Hills and stopped a Mauna Loa lava flow from entering Hilo!

Volcanologists, engineers, emergency agencies and legal experts should meet soon to discuss options for lava diversion, and to make recommendations to government. In the end, of course, only our elected politicians will be able to make final decisions about how best to protect the interests of lower Puna residents.

There might not be time now to protect structures at the Pahoa Marketplace, and Highway 130 will be cut in any event if the eruption continues, but if thousands of homes are eventually threatened makai of Pahoa, it would be good to have evaluated the options for lava diversion in advance.

Jack Lockwood of Volcano was a staff volcanologist at the USGS Hawaiian Volcano Observatory for more than 20 years, but presently is an independent consultant. He is an expert on the feasibility of lava diversion, and worked with Italian volcanologists during the successful lava diversion efforts at Etna Volcano in 1983. He designed and supervised construction of lava diversion structures to protect NOAA’s Mauna Loa Observatory, and worked with the USAF at the Pohakuloa Training Area. Lockwood’s website is www.volcanologist.com.

 

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